Garrel is the son of director Philippe Garrel and actress Brigitte Sy. His grandfather, Maurice Garrel, and his godfather, Jean-Pierre Léaud, are also famous French actors.. He is a graduate of the Conservatoire de Paris.

He was 6 years old when he first appeared onscreen, in the movie Le baisers de secours. It would be more than a decade before appearing in another movie, Ceci est mon corps. It wasn't until 2002, however, that Garrel gained international recognition playing Eva Green's twin brother in The Dreamers. Director Bernardo Bertolucci found him on the first session of casting in Paris. Garrel has since then starred in various French films before being awarded the 2006 César Award for Best Male Newcomer for his work in Les amants réguliers, directed by his father and featuring his grandfather in a supporting role. He showcased his singing ability in the Christophe Honoré-directed film Les Chansons d'amour.

In 2008, Garrel was the writer and director of the short film "Mes copains".

He is in a relationship with Valeria Bruni Tedeschi - the older sister of French First Lady Carla Bruni. Bruni Tedeschi adopted an African baby in 2009. Aside from his native French, Garrel speaks fluent English and Italian.

1982 Christophe Malavoy · 1983 Richard Anconina · 1984 Pierre-Loup Rajot · 1985 Wadeck Stanczak · 1986 Isaach De Bankolé · 1987 Thierry Frémont · 1988 Stéphane Freiss · 1989 Yvan Attal · 1990 Gérald Thomassin · 1991 Manuel Blanc · 1992 Emmanuel Salinger · 1993 Olivier Martinez · 1994 Mathieu Kassovitz · 1995 Guillaume Depardieu · 1996 Mathieu Amalric · 1997 Stanislaus Merhar · 1998 Bruno Putzulu · 1999 Eric Caravaca · 2000 Jalil Lespert · 2001 Robinson Stévenin · 2002 Jean-Paul Rouve · 2003 Grégori Derangère · 2004 Gaspard Ulliel · 2005 Louis Garrel · 2006 Malik Zidi · 2007 Laurent Stocker